Designers of absorbent and non-absorbent articles strive to improve the tactile feel of materials, increase breathability of the article, and improve hand. Designers also desire to improve the fit of articles by incorporating elastic zones, panels, or other elastic components. However, materials that have a pleasing tactile feel and hand are generally non-elastic, and materials that are elastic generally do not have a pleasing tactile feel and hand. Therefore, a dichotomy exists between providing elasticity and providing a pleasing feel and hand.
U.S. Pat. Nos. 5,143,679, 5,156,793 and 5,167,897 to Weber et. al. describe methods for incrementally stretching a portion of an article constructed from a laminate of a non-elastic material having a pleasing tactile feel and an elastic material, the stretching to impart the laminate with elasticity. More particularly, Weber stretches the waistband portion of a diaper by passing the laminate between intermeshing gear rolls. When the stretching force is removed, the laminate retracts, causing the non-elastic layer to shir or bulk. The resulting laminate has limited elasticity. Because it is necessary for the fibers of the non-elastic layer to remain unbroken in order for them to shir or bulk, the elastic laminate stretches easily only up to the point where it was previously stretched. Thereafter, the laminate strongly resists additional stretching, because the non-elastic layer must be stretched for the laminate to continue stretching. Furthermore, the Weber laminate is not apertured or breathable.
Another laminate is described in U.S. Pat. Nos. 5,422,172, 5,592,690, 5,634,216, and 5,861,074 to Wu. In these patents, Wu describes a method that is very similar to the Weber method, except that Wu stretches an entire laminate web. The web is a laminate of an elastic layer that is extrusion laminated to a non-elastic nonwoven layer. The laminate web is stretched with intermeshed gear rolls, and thereafter, can elastically stretch up to 150% its original length. As with the Weber laminate, the Wu laminate bulks after stretching, indicating that the fibers remain unbroken. Therefore, the Wu laminate stretches easily only up to the point where it was originally stretched (here up to 150% of its original length), because it is limited by the unbroken fibers of the non-elastic nonwoven layer. The Wu laminate is not apertured.
In addition to feel and hand of the materials used in articles, it is often important that the materials be breathable. Breathability is less of a concern in side-tabs, elastic ear and other fasteners, such as those disclosed in U.S. Pat. No. 6,255,236, as it is in side panels, which conform intimately to the body of the wearer. Apertured or otherwise gas permeable elastic films permit breathability of the film while maintaining good conformability. Additionally, the breathable elastic layers permit evaporation of perspiration and increase the circulation of air within the absorbent article. Air circulation is particularly beneficial, as it reduces the sticky feeling experienced by many wearers during use. As elasticity is improved, the conformity of the article increases, and it thus becomes increasingly important that the article be breathable since air cannot escape between the article and the wearer's skin. Neither of the laminates disclosed in the Weber patents and the Wu patents are apertured.
Accordingly, there is a need for an improved elastic composite that is not limited by the non-elasticity of the layers, yet has a pleasing feel and hand. Furthermore, there is a need for an elastic composite with pleasing feel and hand, as well as breathability.